Field of the Invention
The present invention relates to an optical head and an imaging device, and more particularly, to an optical head and an imaging device using a flexible nano layer for formation of dynamic nano aperture.
Background of the Related Art
Nano convergence market has been expanding rapidly at an annual growth rate of 21.3% from 835.4 billion dollars in 2013 and is expected to reach 1 trillion, 974.9 billion dollars by 2017. When considering that nano technology is not commercialized yet, economical and industrial values of the nano technology will become great in the future.
Further, nanoimaging technology may be utilized in bio/medical fields as well as nano-device field. As medical paradigm is shifted from treatment to prevention, the demand for disease prediction technology through neuron signal transmission system analysis and molecule/bacteria imaging is drastically increased, and the mass production of technologies and products with which in-vivo diagnosis can be performed is required over the whole world.
The nanoimaging technology can be applied to a variety of fields. Referring first to the bio field, the most desirable measurement method for the understanding of body phenomenon in biology and medical research is performed on in-vivo measurement, and so as to acquire more detailed body information through the in-vivo measurement, an endoscope system, in which a confocal microscope, an optical coherence tomography, and a ultrasonic microscopy are adopted, is developed and used upon the in-vivo measurement and analysis of the body phenomenon. The measurement techniques applied to the current endoscope system have respective advantages and disadvantages, and further, it is hard for them to conduct precise analysis in the in-vivo state due to their limitation in resolution.
So as to analyze molecule-scale variations generated in cell units and cells, an image can be made in a small field of view and with ultra-high resolution through nanoimaging technology like AFM and NSOM, but there is a limit in imaging speed, so that it is impossible to perform in-vivo nanoimaging for various functional variations and interactions in cells or among cells distributed in a large area.
If the type of disease and the treatment method are selected through fine tissue analysis in the process where the disease is diagnosed and treated, currently, a cell tissue is picked and the in-vitro analysis for the cell tissue is conducted through an external measurement system.
In case of the diagnosis of the disease through the in-vitro analysis, however, it is hard to provide the diagnosed result rapidly and further to measure the response in the body in real time.
When current nanoimaging technology is applied to the in-vivo measurement, on the other hand, there is another big problem in that a sample does not have any flat shape and further works in real time. The current nanoimaging technology allows the measurement of the sample to be conducted in the state of maintaining a given gap from the sample and continuously connects very small fields of view to form one image. Since a measured object in the body is kept working, in this case, the existing nanoimaging technology having a slow frame rate cannot acquire accurate real-time images, and when curved-shaped body tissues kept working are measured, further, it is impossible to maintain a given gap from the body tissues accurately.
In case of display field, substrate sizes have been increased day by day, and now, mass production for tenth generation substrates (3080 mm×2500 mm) has been conducted. Further, large-area substrate trend will be kept for a period of time. In addition to the large area, on the other hand, the number of high resolution display products in the display field has been increased by the demand of consumers, and the market share of products having 400 ppi or more is expected to increase. Accordingly, the demand in industrial fields for the mass production of the large-area high-speed and high-resolution on-machine inspection equipment as well as semiconductor inspection equipment is expected to increase rapidly.
Recent subjects of the research and development of electronic devices like semiconductors and displays are high integration, large area and flexibility. In addition to the semiconductor field in which nano-scale patterns are already applied, ultra high density (UHD) display technology is applied in the display field, so that the nano-scale patterns will be adopted in the display field. Accordingly, there is a need for development of on-machine nanoimaging technology capable of conducting total inspection on the nano-scale patterns every process.
Commercial optical inspection/measurement equipment has a resolution of micrometer units, so that the equipment is utilized in the on-machine imaging process in the current display field, but it is not utilized in the semiconductor process having the nano-scale units. Further, the degree of utilization of the equipment in the display field will be decreased. There are SEM, AFM and NSOM as current nano-scale inspection equipment, but they have many limitations in application to on-machine imaging.
Particularly, it is hard that flexible electronic devices like flexible display, wearable computer and so on are applied to the existing fixed focus type imaging inspection system due to the flexibility of the substrate.
The most important key point for enhancing the energy efficiency in the nano-energy field where nano materials/devices are applied is to desirably design the diffusion lengths of the excitons and charges on the active layer of solar cells and on the battery electrodes. However, most of research conducted until now just measures the diffusion lengths in an indirect way (indirect calculation through photocurrent measurement or spectra measurement), so that the measurement is under the influence of the measurement environments and the surrounding materials constituting the devices, thus making it hard to conduct the measurement accurately.
Recently, technologies capable of measuring the diffusion lengths in a direct way through source lasers, like scanning photocurrent microscopy (laser-beam induced current technique) and scanning laser-spot technique, have been developed, and they can be utilized in the desirable combination and design of nano materials and devices. In the nano-energy field where the nano materials and devices are applied, however, the exiting technologies have had many restrictions in manufacturing the large area imaging device and measuring the uniformity of the diffusion lengths.
As the nano convergence technologies have been rapidly developed, as mentioned above, the measurement and analysis of the nano-scale structures and physical phenomenon are needed in various fields, and the nano-scale measurement technologies, such as, SEM, AFM, TEM, NSOM and so on have been developed very rapidly. Among the various nano-scale measurement technologies, the technology capable of conducting the in-situ/on-machine/in-vivo measurements is optical nanoimaging, and a near-field optical system like NSOM is used as the existing optical nanoimaging technology.
However, the optical imaging system using near field requires the control of a gap of tens of nanometers, thus making it hard to be applied to a parallel optical system. Accordingly, the optical imaging system using near field has limitations in large area imaging, and it is impossible to conduct the imaging for a sample having a curved shape.
FIG. 1 is a perspective view showing near-field nanoimaging, and FIG. 2 is a sectional view showing near-field nanoimaging wherein probes are connected in parallel to each other.
As shown in FIG. 1, near-field nanoimaging has a limit in the application of large area imaging due to a small imaging area, and further, a gap (tens of nanometers) should be maintained for the imaging.
So as to overcome the small imaging area as shown in FIG. 1, FIG. 2 shows probes connected in parallel to each other. In this case, however, if a measured object has a curved shape, an area on which near-field light is revealed and an area on which near-field light is not revealed are generated together, thus making it hard to obtain uniform imaging. So as to apply the near-field nanoimaging to the large area, that is, the uniform imaging for the measured object should be achieved, and accordingly, the conventional near-field nanoimaging has a limit in the shapes of the measured object.